Thousands of UK jobs are at risk as British Gas owner Centrica looks to axe a further 4,000 roles under a ramped-up efficiency programme following a 17% drop in annual profits.

Centrica has confirmed that the majority of those cuts will affect both its UK home and business units over the next three years, as it looks to meet a higher cost-cutting target of £1.25bn per year by 2020.

The company's British workforce was already slashed by 2,100 roles on a like-for-like basis in 2017, taking the total number of job cuts to 5,500 since the start of 2016.

It came as Centrica reported a whopping 92% fall in adjusted operating profit at its UK business unit to just £4m for the full year to December 31, while its UK home arm managed a 1% rise to £819m.

It compounded pain caused by a drop in its North American business unit, resulting in a 17% fall in group adjusted operating profits to £1.25bn, although on a statutory basis, operating profits plunged 80% to £486m.

Centrica said political meddling in the UK energy market had impacted its performance.

Group chief executive Iain Conn said: 'The combination of political and regulatory intervention in the UK energy market, concerns over the loss of energy customers in the UK, and the performance issue in North America have created material uncertainty around Centrica and, although we delivered on our financial targets for the year, this resulted in a very poor shareholder experience.

'We regret this deeply, and I am determined to restore shareholder value and confidence.'

The total number of customer accounts at its UK home division slumped 6% to around 20.3 million, while its UK business unit saw a 9% drop to 653,000.

Centrica said in November that cost cuts would help hold annual earnings at its British Gas arm 'broadly' flat on a year earlier, in spite of customer account losses and a drop in demand for energy due to unseasonably warm autumn weather.

The energy group said on Thursday that its £740m cost-cutting programme had been delivered three years early, having made another £308m in savings in 2017.